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346 APPENDIX IX gases flowing immediately below it, thus decreasing the thickness of the stream and increasing the thickness of the eddy of cooler gases below it. It is to be regretted that the bureau did not make surge observations in this boiler setting as they would have been par- ticularly interesting. This particular setting is an extremely good example of what should not be done. In his book, Fours a Flamme, Professor Groume-Grjimailo makes the following comment upon boiler settings: " The builders of boilers very rarely pay any Combustion of Solid Fuel 32* 2S* 24* 20 % 1C* 12* s* 4* — ^- ----- ' ^. E de J 2CO» 1-Le Chi teller Exother Dic /^ c+o « 2coC° L — 39 L- + 29.1 Endothe Exother •mic / nic / _ Curve of Disso of CO iation C+Oo CO+ 0> ,C02 L-+97.6 L-+68.2 Exothermic/ 3(CO Exothermic i/ )+5(CO. )- i.oci x prcscnc of N«) — -^ ^ 19300 ,L< T g.nep 4CO-o) "1 (1-5 COs)2 J.Crcoustt ut ^ V ./ / V- - Curve f Dissoci of COS ition / \ ^ ^^ ~— ----- _ ~ ____ rnl .I-....I.I-- 400° 500° 700° 800° 900° 1000° 1200° FIG. 180. — Equilibrium Curves of CO and C02 in the Presence of Nitrogen. In the combustion of solid fuel the reaction occurs with a rising tempera- ture CO-2Tl-C = 2CO when the temperature drops, particularly in the presence of iron oxide the reaction reverses, attention whatsoever to the rational distribution of the hot gases. These defects are extremely common in the most recent designs of water tube boilers; this is the explanation of the numerous systems of bafflings and obstructions of the gas passages which are intended to distribute the hot gases in such a manner that they will bathe regularly and uniformly the tubes of the boiler. In reality it is not necessary to have any baffling or distributing walls. The hot gases will rise of their own accord and the heat will be regularly and uniformly distributed to all parts of the boiler.77 The setting designed by A. Bement is shown in Bureau of Mines